In the past, manufacturers of miniature fluorescent lamps have relied heavily upon the personal skill and intuition of numerous skilled artisans.
For example, a miniature fluorescent lamp might be manufactured as follows:
Several glass tubes with the phosphors already deposited therein might be placed in an oven with a single temperature gauge and the temperature raised in order to affect a degassing of the coated tubes. The tubes will be sealed at one end and filled from the other with argon and then evacuated. The process is repeated several times in order to remove the contaminants, which are a by-product of the degassing process.
The artisan will manually control valves, to adjust the pressure in the lamp. While this method has been employed in the past, and has been used to make numerous miniature fluorescent lamps, it does have several serious drawbacks.
First, placing several lamps in a single oven with a single temperature gauge causes temperature uncertainty due to even heat distribution in the oven. This can result in unpredictable gas pressure in the finished fluorescent lamp.
Secondly, the repeated back-flushing approach toward removing the contaminants from the degassing process fails to effectively remove all the contaminants from the lamp.
Finally, there exists a need for improvement in the apparatus and method for manufacturing miniature fluorescent lamps to provide for greater consistency in the characteristics of the lamp.